1901-2.] Mr J. Fraser on Constitution of Matter and Ether. 49 
uate on the line joining her own centre with that of the sun, but 
on the line joining her centre with the position occupied by the 
sun’s centre about 8 J minutes previously ; in fact, with the optical 
sun’s centre. And the centre of the sun’s motion, or that portion 
of his motion influenced by the earth, would be situate on the 
line joining his own centre with the position occupied by that of 
the earth 8 J minutes before ; that, for the sun, would be the optical 
earth. The earth would be continually pressed towards the 
position occupied by the sun when he intercepted the radiations, 
the lack of which at the moment is producing a difference in 
pressure. In fact , she never could even begin to revolve round any 
other but this point .* But this circumstance, so far as I can see, 
being no mathematician, can make no difference ; for the earth 
would revolve round the point where, in a manner of speaking, 
she felt the sun to be ; and the sun, in the same manner of 
speaking, would revolve round the point where he felt the earth 
to be. Remembering that no new motion can be generated ex- 
cept in the direction where there is a deficiency of pressure, it is 
difficult to see how the non-instantaneity of gravity can produce 
either acceleration or retardation in the earth’s motion. If any 
material amount of either acceleration or retardation can be proved 
to follow from the principles of this theory, I am willing to 
reconsider it, being persuaded in my own mind that a natural 
explanation can be found for any discrepancy that may exist ; for 
the coincidences where a natural explanation was found for every 
difficulty which occurred up to now, are too numerous to apply to 
any but a true theory. 
The Thermo- dynamical and Chemical Aspects of the Theory. 
It remains now to say a few words on the thermo-dynamical and 
chemical aspects of the theory • but before doing so, I should like 
to confess that all the little knowledge of chemistry which I 
possess has been acquired with a view of trying if its leading 
principles can be explained by this theory. I have neither the 
time nor the patience to dip deeply into the subject, knowing, as I 
* I doubly emphasise this point, for it would be as though the sun existed 
there and nowhere else. 
PROC. ROY. SOC. EDIN. — VOL. XXIY. 
4 
